The abrasive wear behavior of tungsten-carbide iron-aluminide composite materials was investigated using a pin-on-drum wear-testing machine. Samples were prepared by uniaxially hot pressing blended ...powders. The wear rates of specimens containing 40
vol.% matrix of atomic composition, Fe
60Al
40, were measured and results compared with those of conventional WC–10
vol.% Co hardmetal. They were found to be comparable to those of WC–10% Co hardmetal, when abraded by 120
μm SiC papers under identical conditions. The wear resistance of WC–Fe
60Al
40 composites increased with reduction in WC-grain size and associated with increase in composite hardness. Scanning electron microscopy revealed that the wear surfaces of WC–40% Fe
60Al
40 composites and WC–Co hardmetal were similar in appearance. The higher hardness and work hardening ability of Fe
60Al
40 binder, as compared to Co metal, are believed to be responsible for the excellent abrasive wear resistance of WC composites containing iron aluminide binder.
Electric discharge assisted mechanical milling can be applied to the synthesis of a range of fine powder products, including nanocrystalline agglomerates and individual nanoparticles and ...nanofragments. Processing variables include: starting powder sample size; electric arc parameters such as arc length and arc voltage/current; mechanical milling parameters; gas atmosphere and ionized gas species present. We describe results of an initial experimental program underway to investigate phase transformations and/or particle fragmentation during discharge milling using a new pulsed power supply working at frequencies in the kHz range. The aims were to determine processing parameters required for the synthesis of potentially useful high surface area particles, nanostructural powders and nanoparticles and to compare products with those synthesised by Hz frequency discharge milling.
Microstructural, morphological and phase changes induced by kHz discharge milling were characterised by X-ray diffractommetry and transmission electron microscopy. Results were found to depend on the often competing processes of fragmentation into nanoparticles, agglomeration of powder particles, particle melting and/or sintering and chemical reaction induced by mechano-processing in the presence of a particular type of plasma. Discharge milling of graphite under Ar/4% H
2 resulted in a range of products including: graphite nanostructures, carbon nanotubes and other exotic nanofragments. It was found that, compared with processing at 50
Hz, high frequency (kHz) electric discharge assisted mechanical milling of graphite resulted in higher yields of carbon nanofragments. Discharge milling of hematite resulted in partial reduction to magnetite and FeO and the formation of nanostructural oxide nanorods and nanorod clusters. Discharge milling of Co–WC resulted in products including: micron and submicron fracture products, nanostructural regions of Co and WC and carbon rich nanorods.
Vapour deposition of titanium nitride on WC/Co or hard ferrous-based cutting tips generally results in significant increases in cutting tool life. However, a major limitation of such nitrided tips is ...that they cannot be resharpened for re-use. Although monolithic TiN may be too brittle for cutting tool applications, with appropriate microstructural design, Ti–TiN composites should have the required combinations of toughness, ductility, hardness, wear resistance and thermal conductivity to replace coated tips for a range of machining applications. We report the synthesis of monolithic Ti–TiN composites from nanostructural precursor powders. Reactive ball milling of Ti in nitrogen or ammonia under controlled conditions eventually results in the formation of nanostructural TiN. Furthermore, by ending the reaction after an appropriate period a homogeneous and uniform mixture of Ti and TiN phases can easily be produced. Due to the highly reactive, nanostructural nature of the powder product this synthesis route has the potential to eliminate wetting problems generally associated with the current technology of conventional liquid-phase sintering. Moreover, by controlling nitriding gas pressure changes during milling good control of both the Ti to TiN ratio and final crystallite size distributions can be achieved. It was found that precursor Ti–TiN nanostructural powders synthesised in this way can be successfully compacted and liquid phase sintered without sintering aids. Such compacts show high densities and nanoindentation hardnesses in the range of 18–23 GPa. Structural characterization was performed using X-ray analysis, transmission and scanning electron microscopy as well as optical microscopy. The mechanical properties were characterised using micro- and macroindentation techniques.
To avoid the harmful side effects of cetuximab and improve its therapeutic efficacy, egg serum albumin (ESA) was used as a targeting drug carrier moiety for cancer therapy against Caco-2 colon cancer ...cells. The simple improved desolvation method was used to synthesize ESA nanoparticles (ESA-NPs) and cetuximab-loaded albumin nanoparticles (CET-ANPs) with glutaraldehyde as a crosslinking agent. The ESA-NPs and CET-ANPs were spherically shaped, and their sizes and surface potentials were 100 and − 24 nm and 170 and − 20 nm, respectively, as determined using transmission electron microscopy (TEM) and a Zeta potential analyzer. The specific functional groups of the prepared nanoparticles were revealed by FTIR analysis. In the MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay, CET-ANPs exerted the highest antitumor activity after 24 h followed by CET, ESA-NPs, and pure ESA. Combination of CET + ESA-NPs at different IC50 concentrations at ratios of 1:1, 1:2, 2:1, 1:4, 4:1, 1:9, or 9:1 showed significant synergistic effects with a combination index (CI) > 1. Furthermore, the CET either loaded with ESA-NPs or administered in combination (CET + ESA NPs) caused significant apoptotic damage, as well as an S-phase or G2/M cell cycle arrest to the cancer cells, respectively. These were directly linked with a significant upregulation of mRNA expression of
Caspase3
and
Bax
genes and an extreme downregulation of the mRNA expression of
Bcl2,
particularly in the combination treatment group, as compared to the untreated cells. Finally, ESA-NPs improved the effectiveness of cetuximab, strongly caused apoptotic and antiproliferative action with lower systemic toxicity, and could be suggested for the targeted administration of anticancer medications in various nanosystems.
Through qualitative analysis of a dozen semi-structured interviews, this study identifies the issues that limit the ability of accounting education programmes to prepare students for the workplace in ...Libya, a country in the MENA (Middle East and North Africa) region. Factors include: faculty's lack of practical experience; weak links with the profession; a traditional curriculum; teacher-centred pedagogy; traditional forms of assessment; the number and quality of students; limited or outdated resources; and poor physical infrastructure. As a study of the preparation of students for the workplace in a developing country, which takes account of both faculty and practitioner views, this paper also contributes to the limited literature on accounting education in Libya. Considering the findings through the lens of institutional theory concepts leads to recommendations for options that are likely to be relevant not only to Libya but also to the wider MENA region and other developing countries.
A green protocol has been developed for the preparation of 2,2′-(arylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-ones) following the multicomponent condensation reaction between aromatic ...aldehydes and dimedone with excellent yields. The reaction was carried out in water under microwave irradiation in the presence of montmorillonite KSF as a catalyst. The synthesized compounds were used for the functionalization of MCM-41 silica nanoparticles prepared by the modified Stöber method.
Campylobacter jejuni
(
C. jejuni
) are able to colonise and infect domestic poultry and also pose a risk for humans. The aim of this study was to determine the extent of genotypic diversity among
C. ...jejuni
isolates recovered from avian and human sources in Egypt. Furthermore, the short variable region (SVR) of flagellin A (
flaA
) gene was analysed for the presence of allelic variants. Our results showed that
C. jejuni
isolates differ in their capacity to harbour each of the virulence genes alone or when present in various combinations. The
flaA
gene was detected in all
C. jejuni
strains and none of the strains had all the studied virulence genes together. When considering
C. jejuni
strains from the investigated sources, the
cdtC
gene was the most similar, while the
cdtB
and
iam
genes were the most dissimilar. We could identify 13 novel alleles in the analysed strains. The analyses of virulence gene patterns,
flaA
gene sequences and allelic variants showed that
C. jejuni
strains from different sources overlapped largely suggesting potential involvement of poultry in transmitting
C. jejuni
to humans. We also found that the strains isolated from the same host were highly heterogeneous, with chicken strains exhibiting the highest diversity. Moreover, the human strains were clustered closer to chicken ones than to those from pigeon. The results of this study should be taken into consideration when assessing the epidemiology and risk potential of Egyptian
C. jejuni
not only in poultry, but also in humans.
Aim
To describe baseline characteristics and follow‐up data in patients with lipodystrophy syndromes treated with metreleptin in a national reference network, in a real‐life setting.
Patients and ...Methods
Clinical and metabolic data from patients receiving metreleptin in France were retrospectively collected, at baseline, at 1 year and at the latest follow‐up during treatment.
Results
Forty‐seven patients with lipodystrophy including generalized lipodystrophy (GLD; n = 28) and partial lipodystrophy (PLD; n = 19) received metreleptin over the last decade. At baseline, the median (interquartile range IQR) patient age was 29.3 (16.6‐47.6) years, body mass index was 23.8 (21.2‐25.7) kg/m2 and serum leptin was 3.2 (1.0‐4.9) ng/mL, 94% of patients had diabetes (66% insulin‐treated), 53% had hypertension and 87% had dyslipidaemia. Metreleptin therapy, administered for a median (IQR) of 31.7 (14.2‐76.0) months, was ongoing in 77% of patients at the latest follow‐up. In patients with GLD, glycated haemoglobin (HbA1c) and fasting triglyceride levels significantly decreased from baseline to 1 year of metreleptin treatment, from 8.4 (6.5‐9.9)% 68 (48‐85) mmol/mol to 6.8 (5.6‐7.4)% 51(38‐57) mmol/mol, and 3.6 (1.7‐8.5) mmol/L to 2.2 (1.1‐3.7) mmol/L, respectively (P < 0.001), with sustained efficacy thereafter. In patients with PLD, HbA1c was not significantly modified (7.7 7.1‐9.1% 61 (54‐76) mmol/mol at baseline vs. 7.7 7.4‐9.5% 61(57‐80) mmol/mol at 1 year), and the decrease in fasting triglycerides (from 3.3 1.9‐9.9 mmol/L to 2.5 1.6‐5.3 mmol/L; P < 0.01) was not confirmed at the latest assessment (5.2 2.2‐11.3 mmol/L). However, among PLD patients, at 1 year, 61% were responders regarding glucose homeostasis, with lower baseline leptin levels compared to nonresponders, and 61% were responders regarding triglyceridaemia. Liver enzymes significantly decreased only in the GLD group.
Conclusions
In this real‐life setting study, metabolic outcomes are improved by metreleptin therapy in patients with GLD. The therapeutic indication for metreleptin needs to be clarified in patients with PLD.
Based on models resulting from the merging of validated kinetic schemes, four reaction mechanisms were developed to describe the combustion of biodiesel-surrogate/ethanol blends in an HCCI engine. ...The proposed models were then compared to experimental data issued from a modified cooperative fuel research (CFR) engine which can be considered as an HCCI engine. The kinetic scheme displaying the best predictive capabilities, in conjunction with the single-zone HCCI code from the chemkin library, was used to investigate effects of ethanol enrichment and the variation of some important parameters, such as inlet temperature, relative air/fuel ratio and compression ratio, on the combustion and performance characteristics of the investigated HCCI engine. The blended fuels were formed by incrementally adding 10% of ethanol to the neat biodiesel mixture. The inlet temperature ranged from 320 to 420 K with a step of 20 K, whereas air/fuel and compression ratios were varied from 2 to 5 with a step of 0.5, and from 9 to 14 with a step equal to 1, respectively. The obtained data indicated that ethanol effects on the starting of combustion, combustion duration and indicated mean effective pressure were dependent on intake temperature, air/fuel and compression ratios.
Foodborne pathogens have been associated with severe and complicated diseases. Therefore, these types of infections are a concern for public health officials and food and dairy industries. Regarding ...the wide-spread multidrug resistant (MDR) and extensively drug resistant (XDR) foodborne pathogens such as
Enteritidis (
Enteritidis), new and alternative therapeutic approaches are urgently needed. Therefore, we investigated the antimicrobial, anti-virulence, and immunostimulant activities of a stable formulation of thymol as thymol nanoemulsion in an in vivo approach. Notably, treatment with 2.25% thymol nanoemulsion led to a pronounced improvement in the body weight gain and feed conversion ratio in addition to decreases in the severity of clinical findings and mortality percentages of challenged chickens with XDR
Enteritidis confirming its pronounced antimicrobial activities. Moreover, thymol nanoemulsion, at this dose, had protective effects through up-regulation of the protective cytokines and down-regulation of XDR
Enteritidis
virulence gene and interleukins (
)
and
cytokines as those hinder the host defenses. Furthermore, it enhanced the growth of gut
species, which increases the strength of the immune system. For that, we suggested the therapeutic use of thymol nanoemulsion against resistant foodborne pathogens. Finally, we recommended the use of 2.25% thymol nanoemulsion as a feed additive for immunocompromised individuals as well as in the veterinary fields.
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